Development of reduced-order models for aeroelastic analysis and flutter prediction using the CFL3Dv6.0 code (original) (raw)
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CEAS Aeronautical Journal, 2015
We implement reduced order modelling techniques for aeroelastic predictions of the HIRENASD and S 4 T wings in order to represent CFD based high-fidelity solutions efficiently. Model reduction techniques such as non-intrusive Polynomial Chaos Expansion and Proper Orthogonal Decomposition are applied to both static and dynamic aeroelastic cases. The high-fidelity solutions are obtained by fluid structure interaction analysis using a 3D Euler unsteady aerodynamic solver and structural modal solution from a finite element solver. The model order reduction strategy is based on a multidisciplinary approach since both structural and aerodynamic input parameters are employed. The model order reduction is performed not only to represent the high-fidelity computational analyses when small variations of input parameters are considered but also to characterize the flutter responses of the S 4 T wing in a broad range of input values over the entire flight regime for Mach numbers between 0.60 and 1.20. The efficient aeroelastic analyses performed using the developed reduced order models agreed well with the high-fidelity computational analyses.
Proceedings of the 3rd South-East European Conference on Computational Mechanics – SEECCM III, 2013
We investigate model reduction techniques through computational aeroelastic analyses of the HIRENASD and S 4 T wings. The aim of the present work is to construct accurate and computationally efficient reduced order models for high-fidelity aeroelastic computations. Firstly, the aeroelastic analyses of the specified wings are performed by high-fidelity structural and aerodynamic models to substantiate the fluid-structure interaction. Concerning high amount of computational time required to perform such high-fidelity fluid-structure interaction analyses, the model orders are reduced by introducing relevant reduction techniques such as Polynomial Chaos Expansion and Proper Orthogonal Decomposition. The final aeroelastic analyses performed on these reduced models agree well with the initial high-fidelity computational analyses.
Towards Real-Time CFD-Based Aeroelastic Computations Using a Database of Reduced-Order Models
AIAA J, 2010
This paper demonstrates the feasibility of a CFD (Computational Fluid Dynamics)based computational strategy for fast, on-demand aeroelastic predictions of the behavior of a full aircraft configuration at variable flight conditions. The strategy relies on the off-line pre-computation of a database of reduced-order bases and models associated with a discrete set of flight parameters, and its training for an interpolation method suitable for reduced-order information. The potential of this near real-time computational strategy for assisting flutter flight testing is highlighted with the broad aeroelastic identification of an F-16 configuration in the subsonic, transonic and supersonic regimes.
2014
In the past much effort has been made to utilize advanced computational fluid dynamic (CFD) programs for aeroelastic simulations and analyses of military and civil aircraft. Although the use of CFD has become broad for static aerodynamic calculations nowadays, it is limited in the field of unsteady aeroelasticity due to enormous size of computer memory and unreasonably long CPU time associated with the large number of mode shapes in the structural model. While a military airplane model may need 20-50 modes, commercial aircraft models typically require as many as 200 modes to describe the motion of the structure with sufficient accuracy. Thus, both aeroelastic and CFD researchers have explored and developed various ways to reduce the size of the unsteady aerodynamic system and minimize the memory and CPU time. Unfortunately, although these reduced-order models (ROM) retain much of the characteristics of the original full-order models and reproduce the full responses quickly and faith...
Hybrid Finite-Volume Reduced-Order Model Method for Nonlinear Aeroelastic Modeling.
A fully coupled partitioned fluid–structure interaction technology is developed for transonic aeroelastic structures undergoing nonlinear displacements. The Euler equations, written in an arbitrary Lagrangian–Eulerian coordinate frame, describe the fluid domain, whereas the structure is represented by a quadratic modal reduced-order model. A Runge–Kutta dual time-stepping method is employed for the fluid solver, where three upwind schemes are considered, viz., Advection Upwind Splitting Method plus-up, Harten-Lax-van Leer with Contact, and Roe schemes. The Harten-Lax-van Leer with Contact implementation is found to offer a superior balance between efficiency and robustness. The developed fluid–structure interaction technology is applied to modeling transonic flutter, and the quadratic reduced-order model is demonstrated to offer dramatic improvements in accuracy over the more conventional linear method.
Recent Advances in Reduced-Order Modeling and Application to Nonlinear Computational Aeroelasticity
& Proceedings 저널· 프로시딩즈| 기술보고서| 해외 …, 2008
Reduced-order models (ROMs) are usually thought of as computationally inexpensive mathematical representations that offer the potential for near real-time analysis. Indeed, most ROMs can operate in near real-time. However, their construction can be computationally intensive as it requires accumulating a large number of system responses to input excitations. Furthermore, ROMs usually lack robustness with respect to parameter changes and therefore must often be rebuilt for each parameter variation. Together, these two issues underline the need for a fast and robust method for adapting pre-computed ROMs to new sets of physical or modeling parameters. To this effect, this paper reports on recent advances in this topic. In particular, it describes a recently developed interpolation method based on the Grassmann manifold and its tangent space at a point that is applicable to structural, aerodynamic, aeroelastic and many other ROMs based on projection schemes. This method is illustrated here with the adaptation of CFD-based aeroelastic ROMs of complete fighter configurations to new values of the free-stream Mach number. Good correlations with results obtained from direct ROM reconstruction and high-fidelity linear and nonlinear simulations are reported, thereby highlighting the potential of the described ROM adaptation method for near real-time aeroelastic predictions using pre-computed ROM databases. example, in the transonic regime. This cost is such that CFD-based nonlinear aeroelastic codes are applied nowadays to the analysis of a few, carefully chosen configurations, rather than routine analysis.
AIAA Journal, 2010
This paper describes a CFD (Computational Fluid Dynamics)-based computational methodology for fast, on-demand aeroelastic predictions of the behavior of a full aircraft configuration at variable flight conditions, and demonstrates its feasibility. The methodology relies on the off-line pre-computation of a database of reduced-order bases and models associated with a discrete set of flight parameters, and its training for an interpolation method suitable for reduced-order information. The potential of this near real-time computational methodology for assisting flutter flight testing is highlighted with the aeroelastic identification of an F-16 configuration in the subsonic, transonic and supersonic regimes.
This paper describes a computational-fluid-dynamics-based computational methodology for fast on-demand aeroelastic predictions of the behavior of a full aircraft configuration at variable flight conditions and demonstrates its feasibility. The methodology relies on the offline precomputation of a database of reduced-order bases and models associated with a discrete set of flight parameters, and its training for an interpolation method suitable for reducedorder information. The potential of this near-real-time computational methodology for assisting flutter flight testing is highlighted with the aeroelastic identification of an F-16 configuration in the subsonic, transonic, and supersonic regimes.
Reduced-order fluid/structure modeling of a complete aircraft configuration
Computer Methods in Applied Mechanics and Engineering, 2006
... the exclusive use of linear aerodynamic theories for predicting the unsteady aerodynamic forces. ... Because of this computational cost, the potential of CFD-based nonlinear aeroelastic codes ... possible however to address this limitation with the use of reduced-order models (ROMs ...